Question 1

The elongation of the leading strand during DNA synthesis

Accepted Answer

A)  progresses away from the replication fork. 
B)  occurs in the 3′ → 5′ direction. 
C)  produces Okazaki fragments. 
D)  depends on the action of DNA polymerase. 
A)  progresses away from the replication fork. 
B)  occurs in the 3′ → 5′ direction. 
C)  produces Okazaki fragments. 
D)  depends on the action of DNA polymerase. D

Question 2

Thymine makes up 28% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be guanine?

Accepted Answer

A)  8% 
B)  16% 
C)  22% 
D)  72% 
A)  8% 
B)  16% 
C)  22% 
D)  72% C

Question 3

Which of the following statements correctly describes the difference between ATP and the nucleotides used during DNA synthesis?

Accepted Answer

A)  The nucleotides have the sugar deoxyribose; ATP has the sugar ribose. 
B)  The nucleotides have two phosphate groups; ATP has three phosphate groups. 
C)  ATP contains three high-energy bonds; the nucleotides have two. 
D)  ATP is found only in human cells; the nucleotides are found in all animal and plant cells. 
A)  The nucleotides have the sugar deoxyribose; ATP has the sugar ribose. 
B)  The nucleotides have two phosphate groups; ATP has three phosphate groups. 
C)  ATP contains three high-energy bonds; the nucleotides have two. 
D)  ATP is found only in human cells; the nucleotides are found in all animal and plant cells. A

Question 4

In the polymerisation of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer?

Accepted Answer

A)  the 5' phosphate 
B)  C6 
C)  the 3' OH 
D)  a nitrogen from the nitrogen-containing base 
A)  the 5' phosphate 
B)  C6 
C)  the 3' OH 
D)  a nitrogen from the nitrogen-containing base

Question 5

In his transformation experiments, what phenomenon did Griffith (1928) observe?

Accepted Answer

A)  Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. 
B)  Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic. 
C)  Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. 
D)  Mice infected with a pathogenic strain of bacteria can spread the infection to other mice. 
A)  Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form. 
B)  Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic. 
C)  Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains. 
D)  Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.

Question 6

Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA during DNA replication?

Accepted Answer

A)  The leading strand is synthesised in the same direction as the movement of the replication fork, and the lagging strand is synthesised in the opposite direction. 
B)  The leading strand is synthesised by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesised by adding nucleotides to the 5' end. 
C)  The lagging strand is synthesised continuously, whereas the leading strand is synthesised in short fragments that are ultimately stitched together. 
D)  The leading strand is synthesised at twice the rate of the lagging strand. 
A)  The leading strand is synthesised in the same direction as the movement of the replication fork, and the lagging strand is synthesised in the opposite direction. 
B)  The leading strand is synthesised by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesised by adding nucleotides to the 5' end. 
C)  The lagging strand is synthesised continuously, whereas the leading strand is synthesised in short fragments that are ultimately stitched together. 
D)  The leading strand is synthesised at twice the rate of the lagging strand.

Question 7

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

Accepted Answer

A)  One of the daughter cells, but not the other, would have radioactive DNA. 
B)  Neither of the two daughter cells would be radioactive. 
C)  All four bases of the DNA would be radioactive. 
D)  DNA in both daughter cells would be radioactive. 
A)  One of the daughter cells, but not the other, would have radioactive DNA. 
B)  Neither of the two daughter cells would be radioactive. 
C)  All four bases of the DNA would be radioactive. 
D)  DNA in both daughter cells would be radioactive.

Question 8

Which of the following characteristics of eukaryotic telomeres cause them to replicate differently than the rest of the chromosome?

Accepted Answer

A)  The activity of telomerase enzyme. 
B)  DNA polymerase that cannot replicate the leading strand template to its 5' end. 
C)  Gaps left at the 5' end of the lagging strand template. 
D)  Gaps left at the 3' end of the lagging strand because of the need for a primer. 
A)  The activity of telomerase enzyme. 
B)  DNA polymerase that cannot replicate the leading strand template to its 5' end. 
C)  Gaps left at the 5' end of the lagging strand template. 
D)  Gaps left at the 3' end of the lagging strand because of the need for a primer.

Question 9

After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl (1950s) could be confident of which of the following conclusions?

Accepted Answer

A)  Replication is semi-conservative. 
B)  Replication is not dispersive. 
C)  Replication is not conservative. 
D)  Replication is neither dispersive nor conservative. 
A)  Replication is semi-conservative. 
B)  Replication is not dispersive. 
C)  Replication is not conservative. 
D)  Replication is neither dispersive nor conservative.

Question 10

Which of the following types of molecules help to hold the DNA strands apart while they are being replicated?

Accepted Answer

A)  primase 
B)  ligase 
C)  DNA polymerase 
D)  single-strand DNA binding proteins 
A)  primase 
B)  ligase 
C)  DNA polymerase 
D)  single-strand DNA binding proteins

Question 11

In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon?

Accepted Answer

A)  DNA replication is semiconservative. 
B)  DNA replication is conservative. 
C)  DNA replication is not conservative. 
D)  RNA synthesis is conservative. 
A)  DNA replication is semiconservative. 
B)  DNA replication is conservative. 
C)  DNA replication is not conservative. 
D)  RNA synthesis is conservative.

Question 12

DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyses the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed during DNA replication?

Accepted Answer

A)  ribozymes 
B)  DNA polymerase 
C)  ATP 
D)  RNA primers 
A)  ribozymes 
B)  DNA polymerase 
C)  ATP 
D)  RNA primers

Question 13

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

Accepted Answer

A)  8% 
B)  16% 
C)  42% 
D)  58% 
A)  8% 
B)  16% 
C)  42% 
D)  58%

Question 14

A space probe returns with a culture of a microorganism found on a distant planet. Analysis shows that it is a carbon-based life-form that has DNA. You grow the cells in 15N medium for several generations and then transfer them to 14N medium. Which pattern in the figure would you expect if the DNA was replicated in a conservative manner?

Accepted Answer

A)  A 
B)  B 
C)  C 
D)  D 
A)  A 
B)  B 
C)  C 
D)  D

Question 15

In an analysis of the nucleotide composition of a molecule of DNA, which of the following combinations of base pairs will be found?

Accepted Answer

A)  A = C 
B)  A = G and C = T 
C)  A + C = G + T 
D)  G + C = T + A 
A)  A = C 
B)  A = G and C = T 
C)  A + C = G + T 
D)  G + C = T + A

Question 16

Which of the following statements correctly describes the structure of chromatin?

Accepted Answer

A)  Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA. 
B)  Both heterochromatin and euchromatin are found in the cytoplasm. 
C)  Heterochromatin is highly condensed, whereas euchromatin is less compact. 
D)  Euchromatin is not transcribed, whereas heterochromatin is transcribed. 
A)  Heterochromatin is composed of DNA, whereas euchromatin is made of DNA and RNA. 
B)  Both heterochromatin and euchromatin are found in the cytoplasm. 
C)  Heterochromatin is highly condensed, whereas euchromatin is less compact. 
D)  Euchromatin is not transcribed, whereas heterochromatin is transcribed.

Question 17

A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?

Accepted Answer

A)  DNA polymerase 
B)  DNA ligase 
C)  Okazaki fragments 
D)  primase 
A)  DNA polymerase 
B)  DNA ligase 
C)  Okazaki fragments 
D)  primase

Question 18

Who performed classic experiments that supported the semiconservative model of DNA replication?

Accepted Answer

A)  Watson and Crick 
B)  Meselson and Stahl 
C)  Hershey and Chase 
D)  Franklin and Wilkins 
A)  Watson and Crick 
B)  Meselson and Stahl 
C)  Hershey and Chase 
D)  Franklin and Wilkins

Question 19

For a science fair project, two students decided to repeat the Hershey and Chase (1952) experiment, with modifications. They decided to radioactively label the nitrogen of the DNA, rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogen atoms. Thus, labelling the nitrogen atoms would provide a stronger signal than labelling the phosphates. Why won't this experiment work?

Accepted Answer

A)  There is no radioactive isotope of nitrogen. 
B)  Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long. 
C)  Although there are more nitrogens in a nucleotide, labelled phosphates actually have 16 extra neutrons; therefore, they are more radioactive. 
D)  Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins. 
A)  There is no radioactive isotope of nitrogen. 
B)  Radioactive nitrogen has a half-life of 100,000 years, and the material would be too dangerous for too long. 
C)  Although there are more nitrogens in a nucleotide, labelled phosphates actually have 16 extra neutrons; therefore, they are more radioactive. 
D)  Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

Question 20

A heat-killed, phosphorescent (light-emitting) strain of bacteria is mixed with a living, non-phosphorescent strain. Further observations of the mixture show that some of the living cells are now phosphorescent. Which of the following observations would provide the best evidence that the ability to phosphoresce is a heritable trait?

Accepted Answer

A)  Evidence that DNA was passed from the heat-killed strain to the living strain. 
B)  Evidence that protein passed from the heat-killed strain to the living strain. 
C)  Especially bright phosphorescence in the living strain. 
D)  Phosphorescence in descendants of the living cells. 
A)  Evidence that DNA was passed from the heat-killed strain to the living strain. 
B)  Evidence that protein passed from the heat-killed strain to the living strain. 
C)  Especially bright phosphorescence in the living strain. 
D)  Phosphorescence in descendants of the living cells.

Exam 16: The Molecular Basis of Inheritance

The elongation of the leading strand during DNA synthesis

Thymine makes up 28% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be guanine?

Which of the following statements correctly describes the difference between ATP and the nucleotides used during DNA synthesis?

In the polymerisation of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer?

In his transformation experiments, what phenomenon did Griffith (1928) observe?

Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA during DNA replication?

Suppose you are provided with an actively dividing culture of E. coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?

Which of the following characteristics of eukaryotic telomeres cause them to replicate differently than the rest of the chromosome?

After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl (1950s) could be confident of which of the following conclusions?

Which of the following types of molecules help to hold the DNA strands apart while they are being replicated?

In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon?

DNA contains the template needed to copy itself, but it has no catalytic activity in cells. What catalyses the formation of phosphodiester bonds between adjacent nucleotides in the DNA polymer being formed during DNA replication?

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

In an analysis of the nucleotide composition of a molecule of DNA, which of the following combinations of base pairs will be found?

Which of the following statements correctly describes the structure of chromatin?

Who performed classic experiments that supported the semiconservative model of DNA replication?

Evolution, the Themes of Biology, and Scientific Inquiry

The Chemical Context of Life

Water and Life

Carbon and the Molecular Diversity of Life

The Structure and Function of Large Biological Molecules

A Tour of the Cell

Membrane Structure and Function

An Introduction to Metabolism

Cellular Respiration and Fermentation

Photosynthesis

Cell Communication

The Cell Cycle

Meiosis and Sexual Life Cycles

Mendel and the Gene Idea

The Chromosomal Basis of Inheritance

Gene Expression: From Gene to Protein

Regulation of Gene Expression

Viruses

Dna Tools and Biotechnology

Genomes and Their Evolution

Descent With Modification: a Darwinian View of Life

The Evolution of Populations

The Origin of Species

The History of Life on Earth

Phylogeny and the Tree of Life

Bacteria and Archaea

Protists

Plant Diversity I: How Plants Colonised Land

Plant Diversity Ii: the Evolution of Seed Plants

Fungi

An Overview of Animal Diversity

An Introduction to Invertebrates

The Origin and Evolution of Vertebrates

Vascular Plant Structure, Growth, and Development

Resource Acquisition and Transport in Vascular Plants

Soil and Plant Nutrition

Angiosperm Reproduction and Biotechnology

Plant Responses to Internal and External Signals

Basic Principles of Animal Form and Function

Animal Nutrition

Circulation and Gas Exchange

The Immune System

Osmoregulation and Excretion

Hormones and the Endocrine System

Animal Reproduction

Animal Development

Neurons, Synapses, and Signalling

Nervous Systems

Sensory and Motor Mechanisms

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